1. Field of the Invention:
The present invention relates to a carriage moving mechanism for moving a carriage for use in a printer and the like.
2. Description of the Prior Art:
A prior carriage moving mechanism is known for use in for example an impact type printer, etc., wherein a carriage having a printing head, etc., mounted thereon is movably attached to a guide shaft while a travelling motor such as a brushless motor is fixedly mounted on the lower surface of the carriage with a pinion mounted on a rotary shaft of the motor, the pinion being engaged with a metal rack disposed in parallel to the guide shaft.
The carriage moving mechanism serves to move the carriage along the guide shaft by a thrust force produced due to rotation of the pinion in engagement with the rack, the pinion being fixed on the rotary shaft of the motor, by running the moving motor. The carriage travelling mechanism can reciprocate the carriage with use of the positive and negative two directional rotations of the pinion caused by the motor.
However, the prior carriage moving mechanism must mount both ends of the rack on a base frame, etc., so as to permit the rack to be parallel to the guide shaft. Accordingly, mounting and adjustment become difficult. In addition, since the rack is made of rigid metal accurate feed of the carriage is difficult due to backlash produced between the rack and the pinion. Furthermore, the travelling motor is likely to be subjected to additional load in moving of the carriage owing to the backlash as well as an insufficient parallel relation between the guide shaft and the rack.
Moreover, since the rack must have a tooth part formed by cutting a metal raw material with sufficient accuracy to be engaged with the pinion, it requires a high level of manufacturing technology at the sacrifice of its being costly.